Since the X5's introduction in 2000, BMW's M division has refused to tune any of the brand's SUVs, even though that crossover's basic architecture comes from the 5 Series. Now with the intro of the X5 M and X6 M at the New York auto show, BMW is giving in to competition from the Porsche Cayenne GTS and the Mercedes-Benz ML65 AMG. In more certain times, the X5/6 Ms would be surefire profit-makers.
Instead of the M5's 500-horse, 5.0-liter V-10, the X5/6 M are powered by a new version of the 4.4-liter twin-turbo V-8, this one featuring a new exhaust manifold set in the engine's vee. The manifold has one turbo inlet for every two cylinders (normally, it's one inlet per turbo scroll) and swaps out cylinders to get a pulse every 90 degrees. The two Garrett twin-scroll turbos work both sides of the vee, not one per bank. There are a larger intercooler and air cooler than in the standard, production twin-turbo BMW V-8, although the oil cooler and water cooler are the same. The Ms get different camshafts and pistons and a 9.3:1 compression ratio. The cylinder head uses the same aluminum alloy as BMW's diesels.
The new M twin-turbo V-8's max engine speed is 6800 rpm (with turbos spooling to about 16,000 rpm at maximum turbo boost) and the engine produces a heady 502 pound-feet of torque from 1800 rpm on.
The X5/6 M set another BMW precedent, as the first M models with an automatic transmission. The X5/6 M's "sport" mode speeds up shifting among the six gears, and the "M" mode speeds them up even further. Click on the X5/6 M's M mode and all-wheel-drive bias shifts heavily to the rear wheels, making them great drift competition candidates, BMW says. The rear bias is well past 20/80, although BMW says it's not pure rear drive.
The X5/6 M set another BMW precedent, as the first M models with an automatic transmission. The X5/6 M's "sport" mode speeds up shifting among the six gears, and the "M" mode speeds them up even further. Click on the X5/6 M's M mode and all-wheel-drive bias shifts heavily to the rear wheels, making them great drift competition candidates, BMW says. The rear bias is well past 20/80, although BMW says it's not pure rear drive.
BMW allowed a short drive of a preproduction X6 M, its steering setup still two generations away from final production, which begins this fall (X5 and X6 M go on sale late this year). Even in M mode, the X6's ultra-high grip and utter lack of body roll trumped attempts to set the tail loose on tight two-lane curves. The X6 M didn't feel too harsh out there, but we were on mostly tabletop roads outside of Munich. On crustier roads, even the standard X6 is a bit harsh.
Most important these days, the X6 M uses about 10 percent less fuel on the European mileage testing cycle than the M5. You can bet on the twin-turbo V-8 instead of the V-10 when BMW replaces the M5 in the 2012 model year.
Most important these days, the X6 M uses about 10 percent less fuel on the European mileage testing cycle than the M5. You can bet on the twin-turbo V-8 instead of the V-10 when BMW replaces the M5 in the 2012 model year.
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